B.E./B.Tech.Degree Examinations, November/December 2010

Regulations 2008
First Semester
Common to all branches

PH2111 Engineering Physics I
Time: Three Hours Maximum: 100 Marks

Answer ALL Questions
Part A - (10 x 2 = 20 Marks)

1. List down the disadvantages of piezoelectric effect.
2. Compare transmission and refection modes of non destructive testing using ultra-
sonic.
3. Why i s population inversion necessary to achieve lasing?
4. How is electrons and holes confinement made in the active region of hetero-junction
laser?
5. What are the different types of classification of optical fibers?
6. Explain dispersion in an optical fiber.
7. Define black body and black body radiation.
8. What is meant by wave function?
9. An element has a HCP structure. If the radius of the atom i s 1.605ºA, ¯nd the
height of unit cell.
10. What is meant by a `Schottky pair'?

Part B - (5 x 16 = 80 Marks)

11. (a) With a neat diagram explain the method of production of ultrasound using
piezoelectric crystal. (16)
OR
11. (b) (i) With a neat diagram, discuss the principle and inspection method of ultrasonic fa detector. (Marks 12)
(ii) Calculate the velocity of ultrasonic waves in water using acoustic grating. The frequency of the ultrasonic wave generated by transducer is 2
MHz. The diffraction angle measured i s 8'45" in the third order diffraction pattern. Wavelength of laser light used in this experiment i s 6328ºA.
(Marks 4)

12. (a) Discuss the Einstein's theory of stimulated absorption, spontaneous and stimulated emission of radiation. What are the conditions for light amplification?
(Marks 16)
OR
12. (b) (i) What is hologram? What are the necessary steps involved in recording
and reconstruction of a hologram? (Marks 12)
(ii) Compare holography with photography. (Marks 4)

13. (a) (i) Explain the basic structure of an optical fiber and discuss the principle of
transmission of light through optical fibers. (Marks 5)
(ii) Derive an expression for numerical aperture. (Marks 5)
(iii) Brie°y discuss a technique of optical fiber drawing. (Marks 6)
OR
13. (b) Explain the concept of optical fiber sensors and describe in detail about any
two sensors. (Marks 6 + 10)

14. (a) (i) What i s meant by matter wave? (Marks 2)
(ii) Derive an expression for the wavelength of matter wave. (Marks 8)
(iii) Describe an experiment that verifies the existence of matter waves. (Marks 6)
OR
14. (b) Solve Schrodinger's wave equation for a particle in a box (one dimensional)
and obtain the energy and eigen function. (Marks 16)

15. (a) (i) Define atomic packing factor. (Marks 2)
(ii) Calculate the number of atoms, atomic radius, coordination number and
atomic packing fraction for BCC and FCC structures. (Marks 10)
(iii) The distance between successive planes of Miller indices (111) is 2.078ºA
for a metal having FCC structure. Find the atomic radius and volume of
its unit cell. (Marks 4)
OR
15. (b) (i) Define the terms polymorphism and allotrope. (Marks 2)
(ii) Explain in detail the crystal defects and their types. (Marks 14)